Semi-manual???!!!

Our validation manager (a chemical engineer) dropped the term semi-manual control on us last week. She learned it when she worked in production at a previous employer, where it referred to manual control through the PLC / DCS / HMI as opposed to ordinary manual control directly operating a device. For our purposes, manual is manual, regardless of whether it's at the device, a control station or on screen.

Has anyone else heard of semi-manual before?

Mike

Reply to
Mike Lamond
Loading thread data ...

Whatever the controller, arranging "manual" operation so that one drives the controller, rather than the device, eliminated the "bump" usually experienced when changing from manual to automatic. One does this by switching the feedback from the plant to the controller output. The effect on the plant in manual is the same, but switching to auto amounts at most to a step change in the command to a system already under control.

Jerry

Reply to
Jerry Avins

Bit of a loose term, but the broad concept has plenty of merit. One variant could be termed 'assisted manual', where the system does calculations and presents people with information to assist them to make adjustments themselves.

Reply to
Bruce Varley

Besides avoiding the bump there can be other benefits. For example, the PLC in the path might prevent a manual operation to drive something into a critical range. Red rpm range, into an object, etc. Just like the railroad systems in many countries maintain a "machine element" between the throttle the engineer operates and the engine, for example cutting it and applying the brakes if he overruns a stop signal and enters the track section of another train.

Reply to
Joerg

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.